This invention relates to a process for preparing L-glucosone alone or in admixture with other L-sugars, such as L-fructose.
L-sugars are useful as sweetening agents because, as disclosed in U.S. Pat. No. 4,262,032, they are sweet like the D-sugars, but unlike D-sugars, L-sugars are either not metabolized by the body or are metabolized to a lesser extent than the D-sugars. These features make L-sugars desirable as sweeteners for individuals wishing to reduce caloric-intake or for individuals unable to metabolize common sugar sweetening agents without detrimental effects, e.g., diabetics. Another advantage associated with L-sugars include the absence of an objectionable aftertaste commonly experienced with artificial sweeteners such as saccharin and the cyclamates. However, as desirable as the L-sugars are in the foregoing respects, their relative scarcity in nature, particularly L-glucose and L-fructose, the laevo counterparts of the two monosaccharide sweeteners most commonly used today, has prevented their widespread use in foods and beverages or even their being considered for use in such products.
U.S. Pat. No. 4,246,347 to Neidleman, et al., the contents of which are incorporated by reference herein, describes a two-step process for producing D-fructose from D-glucose. The first step is the enzymatic conversion of D-glucose to D-glucosone by employing glucose-2-oxidase or carbohydrate oxidase. The second step is the chemical hydrogenation of D-glucosone to D-fructose.
At the present, there are no teachings in the prior art which indicate that glucose-2-oxidase will convert L-glucose to L-glucosone.